The anus is the name for the muscular area at the very end of the large bowel.
The opening of the bowel is controlled by a ring of muscle (called a sphincter ) that opens and closes to control bowel movements.
Anal Cancer is a rare type of cancer.
The most common type of anal cancer is:
Other rarer types are:
- Basal cell carcinoma
What causes anal cancer?
Here are some of the risk factors for developing anal cancer:
- Human papilloma virus (HPV): This is a viral infection known as HPV. The more sexual partners a person has the higher the risk they have of developing HPV.
- Sexual activity: If a person has anal intercourse they are more likely to develop anal cancer than those who don’t.
- Lowered immunity: This form of cancer is more common in people who have a lowered immunity due to medical conditions, such as HIV.
- Smoking: Smoking cigarettes can increase the risk of anal cancer.
What are the symptoms?
The most common symptoms of anal cancer:
- Pain and/or discomfort
- Bleeding from the anus
- The development of small, firm lumps, not to be confused with piles (haemorrhoids)
- Discharge of mucous from the anus
- Faecal incontinence (a reduced ability to control bowel function)
- May appear as an ulcerated area on the skin of the buttocks
If you have any of these symptoms you should have them checked by your doctor - but remember, they are common to many illnesses other than anal cancer.
How is it diagnosed?
After visiting your GP you will probably be referred to a hospital for some tests. These may include:
- Blood test
- Biopsy. A small sample of cells is taken from the tumour so that it can be examined under a microscope.
- CT scan
- Ultrasound. This is a simple scan that uses sound waves to form a picture of the inside of the abdomen.
- Rectal examination. This is also sometimes known as a PR examination and is where the doctor examines the back passage with a gloved finger.
If the results of the tests show anal cancer, another referral will be made to a doctor who specialises in its treatment.
The stage of a cancer is a term used to describe its size and whether it has spread beyond where it started in the body. It includes:
- Stage 1: Cancer only affects the anus.
- Stage 2: Cancer is bigger than 2cm in size, but has not spread into nearby lymph nodes.
- Stage 3A: Cancer has spread to the lymph nodes near the rectum, or to nearby organs such as the bladder.
- Stage 3B: Cancer has either spread to the lymph nodes in the groin and pelvis, or to the lymph nodes close to the anus, as well as bladder.
- Stage 4: Cancer has spread to lymph nodes in the abdomen or to other parts of the body.
Grading refers to the appearance of the cancer cells under the microscope and gives an idea of how quickly the cancer may develop.
How is it treated?
A team of doctors and other staff at the hospital will plan the treatment. Treatment may be coordinated by an oncologist (a doctor who specialises in treating cancer with chemotherapy), surgeon and a radiologist (a doctor who specialises in treating cancer with radiation).
Treatment may involve:
Most people have chemotherapy to shrink the size of the tumour and to get rid of any cancer cells around the body. This is usually followed with surgery to remove the tumour. More chemotherapy and radiotherapy usually follows.
Chemotherapy for anal cancer
This treatment is often given to people with anal cancer to shrink the tumour prior to surgery. This means that the surgery will be less invasive. Often chemo starts again after surgery to kill any remaining cancer cells and stop them from spreading.
This is called adjuvant chemotherapy.For more information about chemotherapy, go to our chemotherapy fact sheet.
Radiotherapy for anal cancer
Radiotherapy is the use of high-energy rays to destroy cancer cells, while doing as little harm as possible to normal cells. For more information about radiotherapy, go to our radiotherapy fact sheet.
There are some side effects of the treatments for anal cancer which can be found in our side effects fact sheet.
Surgery for anal cancer
There are two main types of surgery:
- Local resection: Used for small tumours on the outside of the anus. Only removes the area of the anus containing the cancer cells.
- Abdominoperineal resection: This is the removal of the anus and rectum. This operation requires a permanent colostomy, which involves diverting the open end of the bowel on to the surface of the abdomen (tummy area), to allow faeces to be passed out of the body into a colostomy bag. The opening on the abdominal wall is known as a stoma.
Although the idea of a colostomy is initially frightening and distressing for many people, most people find that they adapt over time and can return to normal activities.
For more information about surgery, go to our surgery fact sheet.
You may want to check out the fact sheets on the left hand side for more information on related topics.